Process of making indoxyl.



UNITED STATES Patented May 5, 1903.

PATENT OFFICE.

AUGUSTUS BISCHLER, OF BASLE, SWITZERLAND, ASSIGNOR TO THE FIRM OF BASLECHEMICAL WORKS, OF BASLE, SWITZERLAND.

PROCESS OF MAKING INDOXYL.

SPECIFICATION forming part of Letters Patent No. 727,270, dated May 5,1903.

Application filed October 25, 1902. Serial No. 128,820. (No specimens.)

To all whom, it may concern.-

Be it known that I, AUGUSTUS BISCHLER, chemist and doctor of philosophy,a subject of the Emperor of Russia, and a resident of Basle,Switzerland, have invented new and useful Improvements in theManufacture of Indoxyl and its Derivatives, of which the following is afull, clear, and exact specification.

It is known that the yield of indoxyl derivatives obtained by heatingphenylglycin derivatives with caustic alkalies or with caustic alkaliesand lime is too poor for technical use, because the phenylglycinderivatives are for the greater part decomposed by the high temperaturenecessary beforethe indoxyl derivatives are formed.

I have found that the alkali salts of phenylglycin, its homologues andderivatives, such as the alkali salts of phenylglycinorthocar-. boxylicacid,may be transformed into indoxyl, its hoinologues and itsderivatives, respectively, at a temperature at which the phenylglycinand its derivatives are practically not decomposed by heating them for aperiod not too prolonged with anhydrous sodium oxid anda diluent orfluX-such as caustic potash, caustic soda, or mixtures thereof.

The anhydrous sodium oxid has a more powerful dehydrating action thanthat of the alkalies, so that the condensation proceeds at a lowertemperature.

Example I: Ten kilos of the sodium or potassium salt of phenylglycin andtwenty kilos anhydrous caustic potash are heated as much as possiblewith exclusion of air to about 200 centigrade, and then seven kilossodium oxid are added while stirring. As soon as the condensation isaccomplished, which may be determined by means of tests taken out fromthe melted mass, leave the mass to cool, dissolve it in water, andprecipitate (by introducinga current of air) the indigo resulting fromthe formed indoxyl.

Example II: Ten kilos of the disodium or dipotassium salt ofphenylglycin carboxylic acid are heated with 15 kilos anhydrous causticpotash to about 190 centigrade. Then five kilograms sodium oxid aregradually added to the melted mass while stirring. After the mass hasbeen further heated during half an hour it is dissolved in water, andthe indoxyl or indoxyl carboxylic acid contained in the solution isprecipitated by introducing air in the said solution.

In the foregoing examples the anhydrous sodium oxid, the alkali, and thesalt of phenylglycin or of phenylglycin carboxylic acid may at first bepulverized together and the mixture then heated slowly to the requiredtemperature.

It will be seen from the foregoing that my invention for the productionof indoxylic bodies includes in its scope the homologues and derivativesof phenylglycin, and I wish it understood that I do not limit myself tothe employment of the alkali salts of phenylglycin itself in carryingout the invention.

What I claim is The herein-described manufacture of an indoxylic body byheating an alkali salt of a phenylglycin substance with caustic alkaliesand sodium oxid.

In witness whereof I havehereunto signed my name in the presence of twosubscribing witnesses.

AUGUSTUS BISCHLER.

WVitnesses:

AMAND BITTER, ALBERT GRAETER.

